The present invention is directed to the detection of fingerprints and other forensic evidence. The invention provides a novel system for detecting images by ultraviolet light (xe2x80x9cUVxe2x80x9d hereinafter). More particularly, the present invention is directed to a UV-imager system that photographs and provides simultaneous viewing of fingerprints and other evidence.
Special tools are frequently used by law enforcement personnel when evaluating a crime scene to collect forensic evidence that is invisible to the human eye. Examples of such evidence include bodily fluids, fingerprints on porous and non-porous surfaces, forged documents, explosive residue, and trace evidence e.g., hair, fibers, etc. One commonly used tool is a forensic light source that utilizes fluorescent light to detect and record forensic evidence.
A recently introduced complementary tool to the forensic light source is a tool that relies on intensified short-wave ultraviolet (xe2x80x9cUVxe2x80x9d) reflectance instead of fluorescence. Such a UV tool can reveal additional evidence on non-porous surfaces where a forensic light source is not useable or the subject requires processing with powders or fluorescent dyes.
In conventional forensic tools that utilize UV reflectance from a UV source a traditional photograph is taken at the output of an intensifier tube. However, photography at the output of an intensifier is limited in resolution by the number of line pairs/mm specification of each intensifier.
One UV tool that does not rely on the output of an intensifier to obtain a photography is a xe2x80x9cSceneScopexe2x80x9d (trademark) UV-Imager which is a system with a modified Nikon FM2 camera available from Instruments S.A., Inc. The prior art Scenescope utilizes an intensifier and a modified 33 mm camera to provide both non-intensified photography of reflectance of fingerprints on various backgrounds, and simultaneous intensified image focusing and viewing. An intensifier is useful to obtain the focus when using an invisible light source such as UV (200-400 nm) or infrared (above 700 nm) since UV or infrared images will not be visible to, and may be harmful to, the naked eye. The intensifier operates electronically to increase the luminescence of the image and provide a visible wavelength output for example on a video screen. However, one problem with the prior art SceneScope is that the image quality is degraded because a relatively low percentage of UV light is reflected by the 35 mm camera.
Based on the foregoing, there is a need for an improved UV-Imager system.
One embodiment of the present invention is a UV-Imager system that includes a camera. The camera includes a first UV coated mirror and a quartz UV transmissive camera lens. The UV-Imager system also includes a second UV coated mirror coupled to the camera through a lens system, and an intensifier coupled to the second UV coated mirror.